Chris wrote

> And how would you tell when the comb is back in the hive whether the AFB
> scales you are seeing are new or old?

The recommendation here in Australia, where irradiation of AFB infected
material is very common, is to burn brood combs and only irradiate empty
honey combs.  This then overcomes the problem that Chris has alluded to.
Combs that have not been extracted cannot be irradiated as the honey
"explodes" and when sending honey for irradiation, the container can only be
two-thirds filled otherwise it also "explodes".  In case someone asks, we
use irradiated honey for queen candy.

Trevor Weatherhead
AUSTRALIA